Merging two decks, with the same basic cards, but different changes

A friend of mine has put in new information in a deck we both use. Now i want to merge the two decks while also maintaining the changes i´ve made to the deck. However, every time I import the other deck the import screen states, that the cards are identical, even though they aren´t.
Is there a fix?

IIRC, changes are only imported if the notes in the file were modified more recently than your local copy.